Apparatus for dehydrating vegetable materials



4 Sheets-Sheet 1 m f W IiGVo: wm m Filed May S. 1943 A. E. WIGELSWORTH Feb. 1, 1944.

APPARATUS FOR DEHYDRATINGEGETABLE MATERIALS swozerh INVENTOR.

% ATTomvEY.

Fell 1, 1944- A. E. wlGELswoRTl-l APPARATUS FOR DEHYDATING VEGETA-BLE MATERIALS Filed May 5, 1945 4 Sheets-Sheet 2 INVENTOR. Agn/UEE WSE/.swoerh A. lrvw.

BY www ATTQRNEY.

Feb. 1, 1944. A. E. wlGELSwRTH l 2,340,633

APPARATUS FOR DEHYDRATING VEGETABLE MATERIALS Filed May 5. 1943 4 Sheets-Sheet 5 INVENTOR.

ATTORNEY.

Feb. 1, 1944. A` E. wlGELswoR'n-l APPARATUS FOR DEHYDRATING VEGETABLE MATERIALS 4 Shets-Sheet 4 Filedv May 5. 1943 luk. bs

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...IY MR R5 ENQ@ W m, w M W d U m E A Patented Feb. 1, 1944 APPARATUS FOR DEHYDRATING" VEGETABLE MATERIALS Arthur 1E. Wigelsworth,I Los Angeles, Calif., as-v signor to Anabolic Food Products, Inc., Glendale, Calif, a corporation of Delaware f Application. May 5, 1943, SeriaLNo. 4585,739Y

8'Claiins.

This inventionl relates to the dehydration of vegetable materials, such as vegetables, fruits and the like, and particularly toapparatus` for dehydrating such materials byl subjecting them tol direct contact with a moving stream of heated air or other gaseous medium toy causeevaporation ofwater therefrom.

The principalobjectof theinvention. is to provide a new and advantageous` type iof, suchdef hydrating apparatus,.in; which the materialis.'v dried in a uniform and .economical vmanner and. without injury or'impairment ofthe material byr A further object isto. provide an -apparatus in: which the above advantages are obtained and in;

which the ,desired dehydration of the. material may be effected in a relatively short time, where-y by a. large-quantity of material may be dehydrated in a given time, in an apparatus of moderate size.

Another object is to provide an apparatus that is inexpensive in construction and operation, in which the material is not moved 'duringv dehydration, and in which the flow of heateddrying gas is controlled in such Inannerjas to produce uniform and ecient dehydration without injuring the material. By avoiding movement of the material during dehydration, the mechanical handling thereof is reduced to a minimum, thus effecting a saving in cost and at the same time eliminating the possibility of physical damage to the material by excessive handling.

A particular object is to provide anapparatus in which a plurality of separate batches of material may be subjected simultaneously to dehydrating treatment, in which each batch `may be independently removed when dehydration thereof is completedand a new batch introduced in its place, and in which advantageous means are provided for controlling the flow of treated gas in contact with the several batches to provide uniform and efficient dehydration thereof.

Other 'objects'andadvantages of the invention will be pointed' out hereinafter or will'be apparent'from `the following description.

The 'apparatus of the present invention' comprises-a housing provided with partitions that dene a plurality ofseparate'compartments arranged side by sideY and extending transversely of the housing. Doorsare` provided for introduction and Aremoval ofthe vegetable material.x The apparatus further comprises means for 'circulating heated air or loth'ergas through thefrespective compartments longitudinally" thereof.` TheV gas' introducedintoeach*` compartment is- 'at 'rela-A tively high temperature, but as` the heat thereof is transferred to the material to eii'ectv dehydration thereof the gas temperature progressively decreases, so that the material adjacent the gasl inlet end-of each compartment is subjectedto the highest Vtemperature-the materialy in the in-A termediate portion is subjected toan intermediate temperature, and that adjacent-thegas -outlet end is subjected-to a lower temperature, withl corresponding variations-'in' the rate of'deh'ydrationin theseportions. f

I therefore provide means for periodically re' versing,V the iiowof .drying gas. through each `compartmenuwherebythe heated gas'is alternately brought into initiall Contact with the material adjacent the opposite/ends of each-compartment.

By properly controlling the frequency of reversaly of gas flow` with relation to the total time required for dehydration; Iam thus able 'to' dehydrate uniformly all portions of the material without excessive heating or dehydration of any portion thereof. Furthermore, since the dehyg dration thus progresses substantially uniformlyY as the gas flow is'repeatedly reversed, the dehydration of allportionsfis completed in the least possiblek time and with a minimum heat requirement.

The accompanying drawings illustrate a preferred form of apparatus according to this invention, in which heated airf is used as the drying medium. Although` air is generally suitable for the purpose, it will ofcourse be understood that any other desired gas may be introduced into the system, either in place of or along with the air: whichl in the embodimentillustrated, is continutially on the same plane as Fig. 2 butwith thetop wall of the dehydrating compartments partlyv broken away;

Fig. 4 is a transverse vertical section, taken onA line 4-4`in Fig. 1; and

Fig.'5 is a'wiring'diagramillustrating' a circuit arrangement that may' beused for controlling the damper-operating motors.

Thej apparatus is show'n'as comprising? ahelonlow the ground or oor level indicated at 2, and including side walls 3 and 4, end walls 6 and 1, bottom wall 8 and top wall 9. Vertically spaced intermediate walls or partitions II and I2 extend substantially horizontally from the end wall 6 at one end of the housing through the major portion of the length of the housing, the other ends of said walls being spaced somewhat from the other end wall 1 to provide a gas passage space I3 ai; that end of the housing, in which is located a fan I4 for maintaining circulation of air.

The intermediate walls I I and I2 extend across the entire Width of housing I and are spaced from the bottom wall 8 and top wall I2, thus providing a supply duct I5 for heated air below wall Il and a return duct I1 above wall'I2. The duct I1 communicates with the upper end of passage I3. The inlet of fan 4I4 opens 'directly into said passage I3, preferably at both ends of the fan housing as indicated at I8, while the outlet of said fan communicates with supply duct I5 through an opening I9 in a wall 2I that shuts olf duct I6 from direct communication with passage I3.

A plurality of equally spaced vertical walls or partitions 22 extend across the entire width of the housing and between the intermediate walls Il and I2 and serve to define a plurality of separate vdehydrating compartments 25 extending transversely of the housing, alternate ones of said compartments being designated by the reference numerals 25a and 25h respectively, as shown best in Fig. 3. The several compartments are thus arranged side by side in a row and the supply and return ducts extend along the row at opposite sides thereof, the supply duct I6 being shown as extending along the lower side and the return duct I1 along the upper side.

The walls II and I2 separate the compartments 25a and 25h from the ducts IB and I1, but are provided with openings for establishing communication between said compartments and said ducts adjacent each end of each compartment, that,is,'at positions adjacent the opposite side wa1ls3 and 4 of the housing. Thus, wall II is provided with inlet openings 23 and 21 located adjacent the respective ends of each of the compartments 25a and 25h, for establishing communication from supply duct I5 to each of said compartments, and wallY I2 is provided with outlet openings 28 and 29 located adjacent the respective ends of each compartment, for establishing communication therefrom to the return duct I1.

I also provide suitable damper means including damper members movable to closed and open positions with respect to the inlet openings 26 and 21 and the outlet openings 28 and 29 of the several compartments, and means for operating the damper members between these positions. The arrangement of the dampers and operating means is preferably such that, upon movementv of the damper members to one position, open communication is established between certain ones of the drying compartments 25 and the supply duct I6 at one end of such compartments, and between those compartments and the return duct I1 at the other end thereof while the damper members close communicationbetween those compartments and the supply and return ducts at said other end and said one end respectively, and the opposite relation of the dampers is established for theremaining compartments. Periodically, the positions of the dampers are 'rect1on, screw 41 will cause movement of rider reversed. Thus, with the dampers in one position, the heated air from supply duct I6 passes through some of th ecompartments 25 in one direction and through the remaining compartments in the opposite direction, and with the dampers in the other position the direction of flow of the heated drying air is reversed in all compartments.

Referring now to the drawings, I have shown two series or trains of inlet dampers, 3| and 32, movable to open and closed positions with respect to the inlet openings 26 and 21 respectively, and two series or trains of outlet dampers, 33 and 34, movable to open and closed positions with respect to the outlet openings 28 and 29 respectively. In the preferred arrangement shown the dampers are so arranged as to respectively close and open corresponding openings at each end of the alternately disposed compartments 25a and 25h respectively.

The arrangement of the outlet dampers 33 and 34, and the operating means therefor, are clearly shown in Figs. 2 nd 3. Each of these dampers is of suiicient length and width to completely cover one of the outlet openings 28 and 29 respectively, and the several damper members of each train are spaced apart longitudinally, the spacing therebetween being substantially equal to or greater than the length of the respective openings. The dampers are shown as mounted for longitudinal sliding movement in guide channels 36 and are operatively connected and maintained in properly spaced relation by means of bars 31 secured at their respective ends to each pair of adjacent damper members.

In the particular apparatus shown, there are an Vodd number of drying compartments, andin order to conserve space, the damper members for the drying compartment at one end of the row are moved transversely between open and closed positions with respect to the openings of that compartment. Thus, the damper members 33a and 34a shown in Figs. 2 and 3 are slidably mounted in transversely extending guide channels38.

With the dampers in the positions shown, dampers 33 close the outlet openings 28 at one end of the alternate compartments 25h whilev dampers 34 and 34a close the outlet openings 29 at the' opposite end of the compartments 25a, the openings 28 at said one end of compartments 25a 4and openings 29 at vsaid opposite end of compartments 25h being open.

The dampers may be operated by means ofv Aelongated flexible traction means such as wire ropes 4I and 42 guided` by suitably disposed pulleys 43.v VTraction Vmember 4l is secured at' one end to one of the dampers 33, as at 44, and' at the other end to one of the dampers 34 asatv 45. Said member 4I is also secured to a threaded rider 46 operated by screw 41 rotatably mounted in bearings 48. Said screwis operated by a reversible electric motor 49 through suitabledrive means 5I. The other traction member 42 is also 'secured at its ends to one of the dampers 33 andto one of the dampers 34, as at 52 and 53 respectively, and is secured intermediateits ends to the dampers 33a and 34a, as at 54.

Upon operation of motor 49 in the proper di- 46 to the position shown in dotted lines at 46' in Fig. 2. Traction member 4I will thereupon move dampers 33 to the left in Fig. 2, which will in Iturn operate through traction member 42 'td move damper 33ato closed position and. damper- 34a. to open-position, and to move dampers 34y toers, including tractionmembers 511 and 53 andmotor 59. However, the positions of the inlet dampers are the reverse of thoseor the outlet dampers, as will be apparent from-the relativeV positionsof dampers 3l, 32, 33, 341 in Fig. 4.

It will now be apparent that, with the-dampers in the positions shown, air from suppl-yduct` I 6 will enter. the.- compartments 2da-throughopenings 21, willilow through -said compartments'from left to right in Fig. 4, and-w-ill pass-v therefrom throughopenings 28- into-thereturn duct l1. At the. same-time, airfromsaidrsupply duct will enter the-remaining. compartments 25h through openings 26, will ilow.therethrough-fromA right to-left, and will pass therefrom throughopenings 29 into the return duct. Upon reversing the positions of the dampers byoperation of motors. 49- and- 59 as described above, the direction of ow through all the compartments will be reversed.

A suitable. control-circuit for the damper operating motors49 and g-is--shown-in-Fig. 5. Thernotors. are shownasthree-phaseinduction motors adapted to beconnected to three-phase power supply lines 6l, either throughleads 62- and 63 respectively to causerotation of each motor in one direction, or through leads .64 and 65- respectively. to cause rotation ofeach motorin the opposite direction. Reversing switch Stmay4 be operated manually to connect. either pair of leads tothe. supply line-6.1, and a main power supply switch t1 may also loe-provided. Limitswitches. 68, 69, 10. and-1l. are preferablyy pro*A vided, 4for opening and closing the. circuitsthrough the 1eads62., 63, Eiland- 65 respectively.-

These limit switches. are` biased toward closedposition and are moved to open position -by means.

of; suitably positioned lugs. or other actuating members 13, 1li, 'i5 and 16V secured t'o-oneof the damper members of` each train, which engagearms11 of the corresponding switch. The-po sitions of these limit switches. and actuating members for the outlet damper system are-shownin Fig. 3, and those for the inletdamper system are comparably positioned.

With .the outletdampers in the positions shown.

in Fig. 3 andthe inlet dampers in the reverse position as noted above, the limit switches and 69 are held open by engagement of actuating membersfl and ,1d with the corresponding switch. Thus c the. motor circuits 62 and. t3.

and 85, motors 69 and 59- areoperated in .the proper directions tok reversey the positions of both the inlet and outlet dampers. Limit switches 6B and '59 are thereupon closed. When the dampers reach the end of their desired travel to the reverse positions, limit switches 10 and,

'Il are opened to stop the motors, thepositions of the actuating members at this time being lindicated in dottedV lines at 132,111', 15' andkg'if inFig.A

ofthe vrespective dehydrating compartments 2.5.

These openings are norma-lly closed-by doors 82- that are arranged to slide vertically'in guide members 83, whereby the doors may be raised vertically to open position to--provide for introduction into therespective compartments. ofmaterial to be dehydrated, and for removal of the dehydrated material therefrom. The material is ordinarily distributed on suitable pervious trays 84 arranged in vertically spaced rela-- tion on wheeled trucks 85, and a. pair of panels or rails 86 is provided in each compartment for receiving and guiding said trucks. In Fig. 4

I have shown three such trucks disposed within. one oi the dehydrating compartments 25a, thesetrucks being positioned centrally of the length.

of the compartment and between the positions ofthe respective inlet and outlet openings', lso as to provide a free and unobstructed vertical gas passage space 81 at ach end of the compartment, facilitating distribution of gas flow over the entire height of the compartment.

Suitable means are provided for heating the circulated air. For this purpose, I haveV shown a plurality of heat exchange devices 38A located-in the return duct I1. These hea-ting devices mairv be of any suitable type but are shown as cornprising gas fired heaters constructed and arranged to heat the circulated air indirectly by transfer of heat from the hot combustion gases to the air. y

A portion of the air leaving thedehydratingl preferably provided for regulating the quantity of fresh air drawn in through opening 92, to maintain the desired Wet bulb temperature in the system. In the operation of the apparatus, trucks loaded with material to be dehydrated are introduced into one or more of the dehydrating compartments, and fan I4 and heaters 88 are operated to provide continuous circulation of heated air through the dehydrating compartments.

In the compartment 25a shown in Fig. 4, the heated air enters the left end-ofthe compartment through inlet opening 21, flows through compartment as described above and leaves through outlet opening 28. It will be apparent from the above description, that at the samev by the heated air to be heated toa somewhat` higher temperature, and consequently. to be dried more rapidly, than the material adjacent thev opposite ends of the respective compartments.

Openings- 3l are provided in onev oiV the side walls of housing, -as in side-wall 31, at--oneend This After a suitable, interval: of time,V the positions; of the-,dampers are.,reversed; .resulting-fin a reversal of the direction of airflow in the respective compartments, which will serve to equalize the heating and drying eiect and produce substantially uniform drying of all portions of the material.

The apparatus is particularly useful in the drying of vegetables, such as carrots or green leafy vegetables.V A very efiicient utilization of heat is obtained, without injury or impairment of the material due to overheating or unduly prolonged heating, or excessive dehydration, of any portions of the materials.

For the dehydration of` such vegetables, the temperature of the air or other gaseous medium supplied to the drying chambers is in most cases preferably maintained below 175i F. In the drying of carrots, for example, the following temperatures may be obtained:

Dry bulb temperature of air entering dehydrating compartments 160 F;

Dry bulb temperature of air leaving Under these conditions, with the dampers in the position shown in Fig. 4, the temperature of the air coming in contact with the material would be approximately 160 F. at the left side of the compartment, 150 F. at the middle of the compartment, and 140 F. at the right side. When the dampers are reversed, the corresponding temperatures would be about 140 F, 150 F. and 160 F., so that the average temperature to which the material is subjected during a series of successive cycles with the dampers in the two different positions is substantially uniform throughout the entire batch of material in each compartment.

I claim:

1. An apparatus for dehydrating vegetable materials comprising: housing means defining a plurality of separate dehydrating compartments arranged in a row and each adapted to receive material to be dehydrated; a gas circulating and heating system including supply and return ducts extending along said row of compartments at opposite sides thereof; means for establishing flow of gas, from said supply duct to said return duct, longitudinally in one direction through one set of said compartments and longitudinally in the oposite direction through the remaining compartments; and means for periodically reversing the direction of flow of gas through all of said compartments.

2. An apparatus for dehydrating vegetable materials comprising: 'housing means defining a plurality of separate dehydrating compartments arranged in a row and each adapted to receive material to be dehydrated; a gas circulating and heating system including supply and return ducts extending along said row ofl compartments at opposite sides thereof; means for establishing flow of gas, from said supplyA duct to said return duct, longitudinaly in one direction through alternate ones of said compartments and. longitudinally in the opposite direction through the remaining compartments; and means for periodically reversing the direction of flow of gas through all of said compartments. y

3. An appartus for dehydrating vegetable materials comprising: a housing provided with wall means including a plurality of spaced transversely extending partitions and defining a plurality of separate compartments arranged in a row and each adapted to receive material to be dehydrated, said housing being provided with doors for introduction ofV material to, and removal of material from, each of ysaid compartments; a gas circulating and heating system comprising means dening a supply duct extending along said row of compartments at one side whereof and a return duct extending along saidV row of compartments at the opposite side thereof, a fan arranged to receive gas from said return duct and to deliver gas to said supply duct, and means for heating such gas during its passage from the return duct to the supply. duct; said wall means being provided with inlet openings for establishing communication from said supply duct to each of said compartments adjacent each end thereof, and with outlet openings for establishing communication from each of said compartments, adjacent each end thereof, to said return duct; and damper means movable to closed and open positions with respect to said openings.

4. An apparatus for dehydrating vegetable material as set forth in claim 3, said damper means comprising a plurality of damper members movable to one position to close one set of said openings between said supply duct and certain of said compartments at one end thereof, between the supply duct and the remaining compartments at the other end thereof, between said certain compartments and the return duct at said other end thereof, and between said remaining compartments and the return duct at said one end thereof, and to open communication through the remaining openings; and to another position to open communication through said one set of openings and close said remaining openings.

5. An apparatus for dehydrating vegetable materials as set forth in claim 3, said damper means comprising a plurality of damper members movable to one position to close a set of openings between said supply duct and alternate ones of said compartments at one end thereof, between the supply duct and the remaining compartments at the other end theerof, between said alternate compartments and the return duct at said other end thereof, and between said remaining compartments and the return duct at said one end theerof, and to open communication through the remaining openings between said compartments and said supply and return ducts; and to another position to open communication through said set of openings and close said remaining openings.

6. An appartus for dehydrating vegetable materials as set lforth in claim 3, said damper means comprising a plurality of inlet dampers each movable between one position to close the opening between one of said ducts and one of said compartments adjacent one end of that compartment and to open communication through the opening between said one duct and an adjacent compartment adjacent said one end thereof, and another position to open communication through said opening between said one duct andsaid one compartment adjacent said one end and close said opening between said one duct and said adjacent compartment; and said appartus also comprising means operatively connected to all of said dampers to move each damper between said two positions.

'7. An apparatus for dehydrating vegetable materials as set forth in claim 3, said damper means comprising a plurality of inlet dampers movable to a first position to open one set Yof said inlet openings at one end of certain ones of said compartments and at the opposite end of the other compartments and to close the remaining inlet openings, and to a second position to close said one set of inlet openings and open said remaining inlet openings, and a plurality of outlet dampers movable to a rst position to open one set of outlet openings at the opposite end of said certain compartments and at said one end of said other compartments and to close the remaining outlet openings, and to a second position to close, said one set of outlet openings and open said remaining outlet openings; and said apparatus also comprising means operatively connected to all of said dampers to move them simultaneously between said iirst and second positions.

8. An appartus for dehydrating vegetable materials as set forth in claim 3, said damper means comprising a plurality of inlet dampers movable to a first position to open one set of said inlet openings at one end of alternate ones of said compartments and at the opposite end of the other compartments and to close the remaining inlet openings and to a second position to close said one set of inlet openings and open said remaining inlet openings, and a plurality of outlet dampers movable to a rst position to open one set of outlet openings at the opposite end of said alternate compartments and at said one end of said other compartments and to close the remaining outlet openings, and to a second position to close said one set of outlet openings and open said remaining outlet openings; and said apparatus also comprising means operatively connected to al1 of said dampers to move them simultaneously between said first and second positions.l

ARTHUR E. WIGELSWORTH. 

